Feature: Add possibility to load or block SBD watchdog kernel modules. Reason: SBD needs a watchdog device to work. The watchdog device is created by loading one or more watchdog kernel modules. The modules can be configured on a per node basis. Blocking certain modules from being loaded is also often a use case (e.g due to hardware specifics). Result: It is now possible to load and / or block SBD watchdog kernel modules in the role. This makes installed hardware watchdogs available to the cluster.